Abstract

Atomic spin polarization of alkali atoms in the ground-state can survive thousands of collisions with paraffin-coated cell walls. The resulting long spin-relaxation times achieved in evacuated, paraffin-coated cells enable precise measurement of atomic spin precession and energy shifts of ground-state Zeeman sublevels. In the present work, nonlinear magneto-optical rotation with frequency-modulated light (FM NMOR) is used to measure magnetic field-induced spin precession for rubidium atoms contained in a paraffin-coated cell. The magnetometric sensitivity of FM NMOR for the rubidium D2 line is studied as a function of light power, detuning, frequency-modulation amplitude, and rubidium vapor density. For a 5-cm-diameter cell at temperature , the optimal shot-noise-projected magnetometric sensitivity is found to be (corresponding to a sensitivity to spin precession frequency of or a sensitivity to Zeeman sublevel shifts of ).

Received 07 July 2009Accepted 14 August 2009Published online 24 September 2009

Acknowledgments:

We are deeply indebted to Dmitry Budker and Micah Ledbetter for numerous useful scientific discussions, to Valeriy Yashchuk for the design of the magnetic shield system, to Misha Balabas for manufacturing the paraffin-coated cells, to Valentin Dutertre for the design and modeling of the magnetic field coils, to Mohammad Ali for his outstanding technical work in support of this experiment, and to HinYan Chan for work on the laser frequency stabilization apparatus. We thank Khoa Nguyen for his contributions to the early stages of this work, and Ian Lacey and Sahar Muhsin for their important work on the two-laser-beam measurement of synchronous and asynchronous magneto-optical rotation that confirmed the explanation of the light-power-dependent FM NMOR spectra in terms of alignment-to-orientation conversion.

We sincerely appreciate the work of Contra Costa Community College students Morgan Jacobs, Kristopher Pohlman, and Dylan Gorman and Foothill Community College student Jennifer Strange who assembled the magnetic shield system.

This work was supported in part by the National Science Foundation under Grant No. PHY-0652824 and Faculty Support Grants from California State University—East Bay (CSUEB). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect those of the National Science Foundation or CSUEB.